Adjustment means for idler pulley



April 19, 1955 b. w. M ccARTHY 2,706,367

ADJUSTMENT MEANS FOR IDLER PULLEY Filed June 23, 1952 DONALD m MAC Gil/F771,;

- IN VEN TOR.

HUEBNER, BEE/"1L ER, WORREL 8 HERZ/G,

A T T-ORNEKS.

United States Patent ADJUSTMENT MEANS FOR IDLER PULLEY Donald W. MacCarthy, Whittier, Calif.

Application June 23, 1952, Serial No. 295,107

10 Claims. (Cl. 51-148) This invention relates to adjustment means for an idler pulleymore particularly such a pulley as is used in a belt sanding machine.

It is an object of this invention to provide simplified and improved means for angularly adjusting a pulley about two axes transverse of each other and transverse of the axis of rotation of the pulley.

It is another object of this invention to provide improved means for adjusting the position of a sanding belt on the work wheel about which the belt runs.

This invention finds particular application in a belt sanding machine having three coplanar pulleys about which is tightly applied a sanding belt. The belt is generally of fabric and coated with abrasive grains. One of. the three pulleys is motor driven, and the other two pulleys are idler pulleys, the drive pulley being also the work pulley and preferably being rubber covered. For most satisfactory operation of the machine it is necessary that the belt be centered accurately on the work pulley, since, in most cases the belt is just as wide as the work pulley, and if the belt overlaps either edge of the pulley it will tend to absorb undue wear.

It has been discovered in accordance with the instant invention that centering of the belt on the work pulley is very sensitive to the angular adjustment of at least one of the idler pulleys, and that this sensitivity is a function of the angular adjustment about both of the axes which are transverse to the rotation axis of the pulley. More specifically, in the case of a sanding machine having a belt stretched about two lower pulleys and an upper pulley, the upper pulley being directly above one of the lower pulleys, which is the work pulley, the centering of the belt on the work pulley is very sensitive to adjustment of the upper pulley about a horizontal axis paralleling the vertical plane in which the pulleys are disposed, and also to adjustment about a vertical axis.

It is accordingly a specific object of the instant invention to provide simplified and improved means for adjusting such an upper idler pulley in a belt sanding machine about a horizontal axis and about a vertical axis.

In accordance with these and other objects which will become apparent hereinafter, a preferred form of the instant invention will now be described with reference to the accompanying drawing wherein:

Fig. 1 is a side elevation of a sanding machine embodying the instant invention.

Fig. 2 is an end elevation fragmentarily sectioned to show more clearly the pulley adjusting feature.

Fig. 3 is a fragmentary view taken along the section line 33 in Fig. 2.

Fig. 4 is a view taken along line 4-4 in Fig. 3.

Fig. 5 is an exploded perspective showing the parts comprising the pulley adjusting means of the instant invention.

Referring to the drawing, 11 designates an upright, generally flat frame, shaped somewhat like the letter C, and having a base 12 formed integral therewith, enabling the frame to be maintained upright on a work-bench. Strengthening ribs 13 are formed transverse to the plane of the frame 11 for added rigidity. Three pulleys 14, 16, and 17 are rotatably mounted on spaced horizontal axes to the frame 11, and are disposed generally coplanarly in a vertical plane as seen in Figs. 1 and 2. The pulley 17 is the work pulley, i. e., the pulley against which the user presses the part to be sanded, and it should be rubber covered. The other pulleys 14 and 16 may also be rubber covered if desired. About the three pulleys is tightly applied a sanding belt 18, the outer surface of which "ice is coated with abrasive grains 19. The lowermost pulley 17 also constitutes the drive pulley and is fixedly secured to a short shaft 21 passing through the frame 11, to the other end of which is secured a V belt pulley 22. The pulley 22 is coupled by means of a conventional V drive belt to any suitable drive means such as an electric motor.

The pulleys 14 and 16 are idler pulleys. The shaft 23, mounting the pulley 16, is mounted so as to be translated in and out on a shaft support 24 adjustably positioned by a lead screw 26. In this way the pulley 16 may be retracted inwardly so as to loosen the belt 18 and permit its replacement by a new belt when desired. Following replacement of the belt 18, the shaft 23 is again translated outwardly by screwing of the lead screw 26, thereby tightening the belt 18 around the three pulleys.

It has been discovered, in accordance with the instant invention, that the centering of the sanding belt 18 upon the pulley 17 is very sensitive to the angular position of the shaft 27 on which the upper idler pulley 14 is rotatably mounted. In accordance with the instant invention means are provided for adjusting the shaft 27 angularly about two adjusting axes.

Near the upper edge of the frame 11 is bolted a hanger 28 having a vertical bore therein through which passes a first adjustable member in the form of a shaft member 29. The lower portion of the member 29 is enlarged and squared as shown at 31 in Fig. 5, and is bored horizontally as shown at 32. A second adjustable member in the form of an upper bearing support 33 is rotatably mounted to the shaft member 29. This is effected by a pair of ears 34 having bores 36; the ears 34 embrace the squared portion 31 and a pintle pin 37 passes through the bores 32 and 36 to rotatably secure the upper bearing support 33 to the shaft member 29. Press-fitted into the upper bearing support 33 is the stub shaft 27, to which the upper pulley 14 is rotatably mounted by suitable ball or roller bearings, not shown.

The shaft member 29 is rotatably held in position in the hanger 28 by a nut 38 threaded to the upper end 39 of the shaft member 29. Intermediate its threaded end 39 and the shaft portion passing through the hanger 28, the member 29 is squared as shown at 41, and closely about this squared portion fits the square opening 42 formed in an adjusting arm 43 arcuately adjustable in a horizontal plane over the flattened upper surface 44 of the frame 11. A circular opening 46 formed near the other end of the arm 43 receives a closely fitting circular boss portion 47 depending from, and formed integral with, an adjusting finger 48. Passing vertically through the finger 48 and boss portion 47 but off center with respect to the boss 47, is a bore 49 which receives a shaft 51 threaded into the frame 11 and surmounted by a locking knob 52 molded integrally about the upper end of the shaft 51. By screwing down the knob 52 the operator tightens the knob against the finger 48 thereby securing it against arcuate movement. In this way the shaft 51 serves not only as the rotating axis for the finger 48, but also as a securement to hold the finger in place following adjustment.

Since the bore 49 is off center in the circular boss 47, rotation of the finger 48 about the shaft 51 causes a slight arcuate movement of the arm 43 about its mounting shaft 29 in turn causing a slight angular adjustment of the shaft member 29 about its vertical axis of mounting. Suitable washers 53 are interposed between the various moving parts to insure against binding.

The above described angular adjustment of the shaft member 29 is, of course, transmitted directly to the pendent upper bearing support 33 so as to adjust the stub shaft 27, supporting the pulley 14, about a vertical ax1s.

The stub shaft 27 is adjusted about a horizontal axis transverse of the shaft 27 by means of an adjusting member in the form of an adjusting screw 54 threaded through a tapped bore in the frame 11. The end of the screw 54 abuts the upper bearing support 33 in a region below the horizontally disposed pintle pin 37, so that as the screw 54 is threaded in and out it causes angular adjustment of the upper bearing support 33 about the pin 37. A hand-wheel 56 is secured to the opposite end of the screw 54 to assist in threaded adjustment thereof. It

will be readily understood that this adjustment may be effected by any member abutting the upper bearing support 33, which causes angular adjustment of the suport 33.

p The tightness of the belt 18 produces a torque on the upper bearing support 33 about its mounting pin 37, which keeps the support pressed tightly against the end of the screw 54, so that adjustment may be achieved simply by the pressing, or abutting, of the screw 54 against the support 33.

To adjust the stub shaft 27, carrying the upper pulley 14, about a horizontal axis, i. e., the pintle pin 37, it is only necessary for the operator to screw the Wheel 56 in and out to the desired extent, the tension in the belt 18 keeping the support 33 constantly pressed against the screw 54.

To effect adjustment of the shaft 27 about a vertical axis, i. e., the axis of the shaft member 29, the operator loosens the finger 48 by unscrewing the knob 52 slightly. He then swings the finger 48 angularly, which, through its eccentric linkage with the arm 43, causes the shaft member 29 to be precisely and accurately adjusted in order to achieve the desired positioning of the belt 18. With the adjustment complete, the operator tightens down the knob 52 to hold the finger 48, and with it the arm 43, firmly in position.

While the instant invention has been shown and described herein in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is therefore not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent apparatus.

What is claimed is:

1. Adjustment means for an idler pulley comprising in combination a frame, a first adjustable member rotatably mounted to said frame for adjustment about a first axis, a second adjustable member rotatably mounted to said first member for adjustment about a second axis substantially transverse of said first axis, an idler pulley rotatably mounted to said second member on a third axis substantially transverse of said first two axes, and means to adjustably position said second member about said second axis.

2. Adjustment means for an idler pulley comprising in combination a frame, a first adjustable member rotatably mounted to said frame for adjustment about a first axis, a second adjustable member rotatably mounted to said first member for adjustment about a second axis substantially transverse of said first axis, an idler pulley rotatably mounted to said second member on a third axis substantially transverse of said first two axes, and an adjusting member adjustably mounted to said frame and having a portion engaging said second member to adjustably position said second member.

3. Adjustment means for an idler pulley comprising in combination a frame, a first adjustable member rotatably mounted to said frame for adjustment about a first axis, a second adjustable member rotatably mounted to said first member for adjustment about a second axis substantially transverse of said first axis, an idler pulley rotatably mounted to said second member on a third axis substantially transverse of said first two axes, and an adjusting screw threadedly mounted to said frame on an axis substantially paralleling said third axis, the end of said screw engaging said second member in a region spaced from said second axis whereby the position of said screw with respect to said frame determines the adjustment of said second member.

4. In a belt sanding machine, the combination including a frame, a drive pulley rotatably mounted to said frame, a first adjustable member rotatably mounted to said frame for adjustment about a first axis, a second adjustable member rotatably mounted to said first member for adjustment about a second axis substantially transverse of said first axis, an idler pulley coplanar with said drive pulley and rotatably mounted to said second member on a third axis substantially transverse of said first two axes, a sanding belt around said pulleys, and means to adjustably position said second member about said second axis.

5. In a belt sanding machine, the combination including a frame, a drive pulley rotatably mounted to said frame, a first adjustable member rotatably mounted to said frame for adjustment about a first axis, a second adjustable member rotatably mounted to said first member for adjustment about a second axis substantially transverse of said first axis, an idler pulley coplanar with said drive pulley and rotatably mounted to said second member on a third axis substantially transverse of said first two axes, a sanding belt around said pulleys and an adjusting member adjustably mounted to said frame and having a portion abutting said second member to adjustably position said second member.

6. In a belt sanding machine, the combination including a frame, a drive pulley rotatably mounted to said frame, a first adjustable member rotatably mounted to said frame for adjustment about a first axis, a second adjustable member rotatably mounted to said first member for adjustment about a second axis substantially transverse of said first axis, an idler pulley coplanar with said drive pulley and rotatably mounted to said second member on a third axis substantially transverse of said first two axes, a sanding belt around said pulleys and an adjusting screw threadedly mounted to said frame on an axis substantially paralleling said third axis, the end of said screw abutting said second member in a region spaced from said second axis, whereby the position of said screw with respect to said frame determines the adjustment of said second mem- 7. In a belt sanding machine, the combination including an upright frame, three pulleys rotatably mounted to said frame about spaced parallel axes, a sanding belt disposed around said pulleys and between two parallel planes spaced apart approximately the width of the belt, one of said pulleys being a drive pulley, the other two pulleys being idler pulleys, the mounting of one of said idler pulleys to said frame comprising a shaft member rotatably mounted to said frame for adjustment about a first axis substantially paralleling said planes, a pulley bearing support rotatably mounted to said shaft member for rotatable adjustment about a second axis substantially transverse of said first axis, said one idler pulley being rotatably mounted to said pulley bearing support, and an adjusting screw threadedly mounted to said frame, the end of said screw abutting said pulley bearing support at a point spaced from said second axis.

8. In a belt sanding machine, the combination including an upright frame, three pulleys rotatably mounted to said frame about spaced parallel axes, a sanding belt disposed around said pulleys and between two parallel planes spaced apart approximately the width of the belt, one of said pulleys being a drive pulley, the other two pulleys being idler pulleys, the mounting of one of said idler pulleys to said frame comprising a shaft member rotatably mounted to said frame for adjustment about a first axis substantially paralleling said planes, a pulley bearing support rotatably mounted to said shaft member for rotatable adjustment about a second axis substantially transverse of said first axis, said one idler pulley being rotatably mounted to said pulley bearing support, an adjusting screw threadedly mounted to said frame, the end of said screw abutting said pulley bearing support at a point spaced from said second axis, and an adjusting arm secured to said shaft member and movable arcuately with respect to said frame to adjust the position of said shaft member with respect to said frame.

9. In a belt sanding machine the combination including an upright frame, three pulleys rotatably mounted to said frame on spaced, substantially horizontal axes, a sanding belt disposed around said pulleys, one of said pulleys being a drive pulley, the other two pulleys being idler pulleys, the mounting of the higher of said idler pulleys to said frame comprising a shaft member rotatably mounted to said frame for adjustment about a vertical axis, a pulley bearing support rotatably mounted to the lower end of said shaft member for rotatable adjustment about a substantially horizontal axis, said higher idler pulley being rotatably mounted to said pulley bearing support, and an adjusting-screw threadedly mounted to said frame, the end of said screw abutting said pulley bearing support at a point below said horizontal axis.

10. In a belt sanding machine the combination including an upright frame, three pulleys rotatably mounted to said frame on spaced, substantially horizontal axes, a sanding belt disposed around said pulleys, one of said pulleys being a drive pulley, the other two pulleys being idler pulleys, the mounting of the higher of said idler pulleys to said frame comprising a shaft member rotatably mounted to said frame for adjustment about a vertical axis, a pulley bearing support rotatably mounted to the lower end of said shaft member for rotatable adjustment about a substantially horizontal axis, said higher idler pulley being rotatably mounted to said pulley bearing support, an adjusting screw threadedly mounted to said frame, the end of said screw abutting said pulley bearing support at a point below said horizontal axis, and an adjusting arm secured to said shaft member and movable arcuately with respect to said frame to adjust the position of said shaft member with respect to said frame.

References Cited in the file of this patent UNITED STATES PATENTS Oakley Aug. 4, 1908 Mattison Apr. 10, 1928 Sutton Sept. 14, 1948 Emmons May 9, 1950 Murray May 20, 1952 

